I bought one of these a while back to get in some "hip shooting" practice at home. Have been working with it lately in my Remington Tac 14 (very similar to the Mossberg shockwave) and it has already paid for itself. This thing projects a pattern size circles of red dots every time the trigger is pulled and shows you exactly where your shot would have gone. I just spent 15 minutes out on the deck "blasting" every flower pot, flood light, tree trunk, bar-b-que grill and dog food bowl in sight and only quit when by arms got tired.